Volume 13 Issue 6, June 2019

Organic microcavity optical transistors open up opportunities for real-world optical switching at room temperature. Now, an all-optical switch at room temperature, using an organic exciton medium with high quantum yield, brings us a step closer to all-optical logical networks.

A phonon laser made from a levitated silica nanosphere held in a controllable optical trap offers a useful tool for studying phonon–photon interactions.

Ultra-long phosphorescence with an emission colour that can be tuned from violet to green is obtained from an organic phosphor featuring several different emitting centres. Such ‘smart’ materials are promising for applications in displays, sensors and bioimaging.

High-speed optical modulators based on silicon, quantum cascade detectors, a photothermal phase-contrast microscope and spin light-emitting diodes with low threshold current density were highlights of the Japan Society of Applied Physics Spring Meeting.

Net gain of ~10 dB µm^–1 and sub-picosecond switching time are shown at room temperature for optical transistors using polymers in a microcavity.

By nesting a Kerr microresonator in a fibre loop with gain, 50-nm-wide bright microcavity-based soliton combs with a mode efficiency of 75% can be induced at average powers more than one order of magnitude lower than the Lugiato–Lefever soliton power threshold, facilitating real-world applications.

Spatially resolved spectra from millions of pixels and information extraction from three molecules per μm² is now possible using dielectric metasurfaces.

Transduction of valley information to mechanical states in a monolayer MoS₂ resonator can be realized by optically pumping the valley carriers and applying an out-of-plane magnetic field gradient to induce a displacement-dependent valley splitting.

A phonon laser based on an optically levitated silica nanosphere is demonstrated. A lasing threshold—a phase transition from Brownian motion to coherent oscillation—is observed when the modulation depth of the trapping beam power is increased.

Organic phosphors with ultra-long lifetimes and an emission colour that can be tuned by the excitation wavelength are reported.

A hybrid technique of stimulated Raman excited fluorescence that integrates superb detection sensitivity and fine chemical specificity is demonstrated, offering all-far-field single-molecule Raman spectroscopy and imaging without plasmonic enhancement.

Improved understanding of passivation leads to near-infrared perovskite light-emitting diodes with 21.6% external quantum efficiency.

Electron–phonon coupling in a monolayer WSe₂ on a substrate is investigated by femtosecond surface X-ray scattering. Counterintuitively, the absorbed optical photon energy is dominantly coupled to the in-plane lattice vibrations within 1 ps.

A 4 × 4 pixel spatial light modulation scheme based on plasmonics offers high-speed spatial light modulation at the telecommunications wavelength of 1,550 nm.